How to use

getOutgoingEdgeWithLabel

method

in

org.grouplens.grapht.graph.DAGNode

@Nullable
public <T> T tryGetInstance(Class<T> type) throws InjectionException {
  Desire d = Desires.create(null, type, true);
  DAGEdge<Component, Dependency> e =
      graph.getOutgoingEdgeWithLabel(l -> l.hasInitialDesire(d));
  if (e != null) {
    return type.cast(instantiator.instantiate(e.getTail()));
  } else {
    DAGNode<Component, Dependency> node = GraphtUtils.findSatisfyingNode(graph, Qualifiers.matchDefault(), type);
    if (node != null) {
      return type.cast(instantiator.instantiate(node));
    } else {
      return null;
    }
  }
}

/**
 * Get an outgoing edge from this node with the specified label, if it exists.
 *
 * @param label The label.
 * @return An outgoing edge with the specified label, or {@code null} if no such edge exists.
 * If multiple edges have this label, an arbitrary one is returned.
 */
public DAGEdge<V,E> getOutgoingEdgeWithLabel(E label) {
  return getOutgoingEdgeWithLabel(Predicates.equalTo(label));
}

@Nullable
public <T> T tryGetInstance(Class<T> type) throws InjectionException {
  Desire d = Desires.create(null, type, true);
  DAGEdge<Component, Dependency> e =
      graph.getOutgoingEdgeWithLabel(l -> l.hasInitialDesire(d));
  if (e != null) {
    return type.cast(instantiator.instantiate(e.getTail()));
  } else {
    DAGNode<Component, Dependency> node = GraphtUtils.findSatisfyingNode(graph, Qualifiers.matchDefault(), type);
    if (node != null) {
      return type.cast(instantiator.instantiate(node));
    } else {
      return null;
    }
  }
}

  @Override
  @SuppressWarnings("unchecked")
  public <T> T getInstance(Annotation qualifier, Class<T> type) throws InjectionException {
    // All Provider cache access, graph resolution, etc. occur
    // within this exclusive lock so we know everything is thread safe
    // albeit in a non-optimal way.
    synchronized(this) {
      Desire desire = Desires.create(qualifier, type, false);

      Predicate<Dependency> pred = Dependency.hasInitialDesire(desire);

      // check if the desire is already in the graph
      DAGEdge<Component, Dependency> resolved =
          solver.getGraph().getOutgoingEdgeWithLabel(pred);

      // The edge is only non-null if instantiate() has been called before,
      // it may be present in the graph at a deeper node. If that's the case
      // it will be properly merged after regenerating the graph at the root context.
      if (resolved == null) {
        logger.info("Must resolve desire: {}", desire);
        solver.resolve(desire);
        resolved = solver.getGraph().getOutgoingEdgeWithLabel(pred);
      }

      // Check if the provider for the resolved node is in our cache
      DAGNode<Component, Dependency> resolvedNode = resolved.getTail();
      return type.cast(instantiator.makeInstantiator(resolvedNode, solver.getBackEdges()).instantiate());
    }
  }
}